Apparatus for removing dust and other impurities from air and other gases



Dec. 27, 1966 T. B. LOFTHEIM 3,

APPARATUS FOR REMOVING DUST AND OTHER IMPURITIES FROM AIR AND OTHER GASES Filed Nov. 24, 1964 huvENTon.

6301! Lot- United States Patent 3,293,832 APPARATUS FOR REMOVING DUST AND OTHER IMPURITIES FROM AIR AND OTHER GASES Tor Bjorn Loftheim, Uranienborgveien 12, Oslo, Norway Filed Nov. 24, 1964, Ser. No. 413,482 Claims priority, application lgorway, Nov. 23, 1963, 51,03 2 Claims. (Cl. 55407) The present invention relates to apparatus for the removal of dust and other impurities from air and other gases.

It has formerly been customary to use for this purpose apparatus in which a separating member rotates and the separation is effected by rotating whirl-forming centrifugal separation blades distributed around the axis of rotation outside and inclined relative to same, said blades forming primary passages communicating with primary outlets at the periphery of the blades through which a substantial quantity of the practically cleaned gases can be emitted while the remainder of the gases together with the separated dust etc. is conveyed through separate outlets to a secondary housing.

In said apparatus centripetal mechanical separation for the first time was used as a means of separating solids, particularly micro-particles, from air or gases, instead of, as usual, separating by centrifugal force.

However, in connection with separation blades there are between adjacent blades, during rotation of the separating member, spiral formed gas streams, as a vacuum is formed at the rear side of one blade, whereby a stream is produced moving towards the axis along the front side of the subsequent blade, inwardly and forwardly and further outwardly along the rear side of the said one blade.

However, microparticles during the above named conditions will follow the lifting streams of the air or gases radially inwards, but as soon as they, by means of the forwardly curved blades, are aggregated into greater particles, these will by reflection against the surface limiting the separate outlets and/ or by the action of the centrifugal forces, partly be lost through the outlet for cleaned gas and in this manner the effect of the separation is decreased.

The object of the present invention is to reduce in a considerable degree the above mentioned drawback, and according to the invention the spaces between the blades at the inner edges thereof each are provided with extensions limited by surfaces extending opposite to the direction of rotation of the blades and tangentially with respect to a cone whose axis coincides with the axis of rotation.

Preferably the extensions may be formed by plate portions which, from the inner edges of the respective separating blades, each extend rearwardly beyond the inner edge of the subsequent blade and, conveniently along its rear edge, is provided with an outwardly bent rim portion resting against the underside of the plate portion extending from said subsequent blade, approximately at the middle thereof, whereby a trough-shaped extension is formed between adjacent plate portions having its middle plan tangential to a cone whose axis coincides with the axis of rotation of the separating member.

By this arrangement during rotation of the separating member an eddy or quiet zone is produced in each of the extensions, limited by the plate portions, so that greater particles brought along with said spiral formed streams between the blades are received in the extensions and by the action of centrifugal forces slide along, counter to the direction of rotation, the rear side limiting surface thereof, which due to the tangential position of the extensions or troughs may be said to act as roofs therein, and into a secondary chamber.

According to the invention the plate portions constituting the extensions extend rearwardly of the rear end of the blades so that they project into the secondary housing.

The invention is described in the following with reference to the drawing, which shows as an example an embodiment, and in which FIG. 1 shows a side view of the apparatus with the upper half in vertical section, FIG. 2 a cross-section along the line II-II in FIG. 1, FIG. 3 a transverse section, in a somewhat greater scale, of blades with intermediate extensions or troughs, and FIG. 4 a side view of a blade and plate portion.

In the drawing 1 denotes a separating member comprising a rotatably supported shaft 2, around which, cycloneshaped, is distributed a number of separation blades 3 with intermediate spaces 4 which form passages having primary outlets 5 for air or gases which have been substantially cleaned of the dust, etc.

The blades 3 are inclined outwardly from the axis of rotation from the inlet end towards the outlet end and the angle of pitch of the blades decreases with increasing distance from the axis of rotation.

According to the invention each of the blades 3 along its inner edge 3' is provided with a plate portion 7 extending tangentially with respect to a cone whose axis coincides with the axis of rotation, this plate portion 7 ex tending opposite to the direction of rotation of the blade. Plate portion 7 projects rearwardly beyond the inner edge 3' of the subsequent plate. Between adjacent plate portions 7 there are thereby formed tangentially directed extensions 6 of the intermediate spaces 4 between the blades 3. Each of the plate portions 7 along its free edge, may have an outwardly bent edge portion 8 which rests against the under side of the projecting plate portion 7 of said subsequent blade, approximately along the middle thereof, so that said edge portion 8 inwardly closes the extension 6. The extensions 6 thus have the form of a trough. As shown in FIG. 4 the plate portion 7 is extended beyond the rear edge of the blade 3, as indicated at 7. The extensions 7' project to form outlets 9 extending into secondary housing 13.

The primarily iconically shaped separating member 1 is rotatably supported in a housing 10 to which the dustbearing gas is supplied through the gas inlet 11, axially at the smallest end of the conical separating member 1. When the separating member is rotating separation is effected by the rotating whirl-forming blades 3 which form the passages 4 and the outlets 5 through which the substantial quantity of cleaned gases passes into the housing 10 and out through the outlet 12 thereof, while :a smaller part of the gases together with the substantial part of the separated dust etc. are received in the trough-shaped extensions 6 and are conveyed along the same and out through the outlets 9 into a secondary chamber 13 having an outlet (not shown) to a dust collector or secondary cyclone.

Due to the decreasing pitch of the blades towards the outlet and the tangential position of the troughs 6 with respect to a cone whose axis coincides with the axis of rotation, there will be in the latter, as mentioned, an eddy or quiet zone so that said greater particles, which move into the troughs, by the action of centrifugal forces slide along, counter to the direction of rotation, the rear side limiting surfaces of the extensions 6 and into the secondary chamber 13.

With the construction of the separating member above described it has appeared that the effect of the apparatus, especially with regard to microparticles, is considerably increased (-97% of the collected dust).

I claim:

1. Apparatus for separation of dust and other impurities from air and other gases, comprising a stationary housing, a rotary separating member situated in said housing and having a predetermined axis of rotation, said separating member having a substantially conical configuration and having an inner end adjacent to said axis of rotation and an outer end situated at a greater distance from said axis of rotation than said inner end, and said separating member including a plurality of outer separating blades distributed about said axis of rotation and each having a pair of opposed longitudinally extending side edges forming an outer side edge and an inner side edge for each blade, said outer and inner side edges of said blades extending from said inner to said outer ends of said separating member, said blades defining between themselves primary passages and primary outlets through which a substantial quantity of substantially clean gases are emitted, said blades respectively having inner plate portions extending from their inner side edges in a direction opposite to the direction of rotation of said separating member and substantially tangentially with respect to a cone whose axis coincides with said axis of rotation, said inner plate portions of said blades being spaced from and at least partly overlapping each other to define between themselves extensions of said primary passages, respectively, for receiving particles greater than those which flow along said primary pass-ages.

2. Apparatus as recited in claim 1 and wherein said stationary housing has a secondary housing connected thereto at one end thereof and communicating therewith, said plate portions extending beyond said outer ends of said blades into said secondary housing and each plate portion having at its edge distant from the inner edge of the blade to which it is connected an outwardly directed rim engaging the adjoining plate portion at its surface which is directed toward the axis of rotation, so that said plate portions provide said extensions of said primary passages with trough-shaped configurations.

References Cited by the Examiner UNITED STATES PATENTS 1,941,449 1/1934 Sylvan 55-407 2,209,607 7/1940 Nutting 55-407 2,317,785 4/1943 Loftheim 55407 2,780,309 2/1957 LOftheim 55-407 ROBERT F. BURNETT, Primary Examiner. 

1. APPARATUS FOR SEPARATION OF DUST AND OTHER IMPURITIES FROM AIR AND OTHER GASES, COMPRISING A STATIONARY HOUSING, A ROTARY SEPARATING MEMBER SITUATED IN SAID HOUSING AND HAVING A PREDETERMINED AXIS OF ROTATION, SAID SEPARATING MEMBER HAVING A SUBSTANTIALLY CONICAL CONFIGURATION AND HAVING AN INNER END ADJACENT TO SAID AXIS OF ROTATION AND AN OUTER END SITUATED AT A GREATER DISTANCE FROM SAID AXIS OF ROTATION THAN SAID INNER END, AND SAID SEPARATING MEMBER INCLUDING A PLURALITY OF OUTER SEPARATING BLADES DISTRIBUTED ABOUT SAID AXIS OF ROTATION AND EACH HAVING A PAIR OF OPPOSED LONGITUDINALLY EXTENDING SIDE EDGES FORMING AN OUTER SIDE EDGE AND AN INNER SIDE EDGE FOR EACH BLADE, SAID OUTER AND INNER SIDE EDGES OF SAID BLADES EXTENDING FROM SAID INNER TO SAID OUTER ENDS OF SAID SEPARATING MEMBER, SAID BLADES DEFINING BETWEEN THEMSELVES PRIMARY PASSAGES AND PRIMARY OUTLETS THROUGH WHICH A SUBSTANTIAL QUANTITY OF SUBSTANTIALLY CLEAN GASES ARE EMITTED, SAID BLADES RESPECTIVELY HAVING INNER PLATE PORTIONS EXTENDING FROM THEIR INNER SIDE EDGES IN A DIRECTION OPPOSITE TO THE DIRECTION OF ROTATION OF SAID SEPARATING MEMBER AND SUBSTANTIALLY TANGENTIALLY WITH RESPECT TO A CONE WHOSE AXIA COINCIDES WITH SAID AXIS OF ROTATION, SAID INNER PLATE PORTIONS OF SAID BLADES BEING SPACED FROM AND AT LEAST PARTLY OVERLAPPING EACH OTHER TO DEFINE BETWEEN THEMSELVES EXTENSIONS OF SAID PRIMARY PASSAGES, RESPECTIVELY, FOR RECEIVING PARTICLES GREATER THAN THOSE WHICH FLOW ALONG SAID PRIMARY PASSAGES. 